@Meddler, why'd you settle on this Syndra buff?

Syndra currently has the following change on the PBE:

Mana per level: 50 > 63

Nice buff to Syndra's really bad mana issues but I'm curious how you landed on this when you were initially exploring changes to her passive, and ricklessabandon said he even had changes to her W planned. Did you decide buffing her passive would be too big a change going into world's for you guys to be sure she wouldn't be unbalanced, or did you struggle to find satisfying ways to improve Transcendent, so you went for an easy win for now? Or something else entirely.